Caffeine Cutoff Calculator
Find the latest time to drink coffee so it doesn't wreck your sleep.
Drip coffee ≈95mg · Espresso ≈63mg · Cold brew ≈155mg · Green tea ≈30mg
Why this conservative?
Average caffeine half-life: 5 hours. 100mg becomes 50mg in 5h, 25mg in 10h. Residual above 30mg cuts deep sleep (N3) by 40% (Drake 2013). Individual variation ±50% for fast/slow metabolizers.